OS - Open Spring Mountings - Special Range

Sizes OS25, OS50, OS75 & OS100

Originally designed for use with Type IPF Inertia Pouring Frames, the OS Mountings are now widely used to isolate vibration from every conceivable type of rotating and reciprocating machine. Where control of transient motion is required Open Spring Mountings can be used in conjunction with our Viscous Dampers Type SFD.

For applications requiring bolting down the rubber seating pad and grommets ensure that there is no direct metal path between the machine and the seating, thus enhancing the high frequency noise isolation.


Design Features:
  • Nominal 25, 50, 75 & 100 mm deflection colour coded helical steel springs to BS1726 Class B with 50% overload capacity and O/D equal to at least 85% of working height.
  • Can be bolted to supporting structure or free standing on 6 mm thick ribbed rubber seating pad (fitted as standard).
  • Fully height adjustable.
  • Zinc plated metals.
  • No snubbing gives maximum efficiency.

Typical Applications:
  • Axial and Centrifugal Fans.
  • Air Handling Units.
  • Low level pipework.
  • With Inertia bases type IPF for pumps, generating sets and compressors etc.

Application Notes:

  • Isolation Efficiency at Typical Machine Speeds:
    MACHINE SPEEDS (rpm) EFFICIENCY %
    25 mm DEFL. 50 mm DEFL. 75 mm DEFL. 100 mm DEFL.
    300 34.0 75.2 84.7 89.0
    500 83.3 92.3 95.0 96.3
    750 93.2 96.7 97.8 98.4
    1000 96.3 98.2 98.8 99.1
    1200 97.4 98.7 99.2 99.4
    1500 98.4 99.2 99.5 99.6
    1750 98.8 99.4 99.6 99.7
    2000 99.1 99.5 99.7 99.8
The above figures are theoretical values only based on the vertical natural frequency of the sprung system assuming infinitely stiff structural supports.

The effects of high frequency spring coil resonances on low frequency performance are also ignored.

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OS - Open Spring Mountings All Variants